F. Mohamad

Electrical Properties of Amorphous Carbon Thin Films Prepared from Natural Precursor of Camphor

Amorphous carbon thin films have been deposited on silicon substrates at different deposition temperatures ranging from 650–800° C. In this work, a natural product, camphor (C10H16O) is used as a carbon precursor. Use of camphor as a precursor for depositing carbon thin film could be more favorable than any other precursors because its single molecule contains both forms of carbon, one sp2 and 9 sp3 carbon atoms. In other words, camphor had both trihedral (sp2) and tetrahedral (sp3) hybridized bonds while diamond and graphite have completely 100% of sp3 and sp2 bonded in their lattice respectively. The electrical properties have been studied using IV measurement. These a‐C films are also characterized using UV‐Vis Spectrophotometer. It was found that increasing deposition temperature had the most influence on the a‐C thin films properties.

Electrical properties of a-C thin film deposited using methane gas as precursor

Amorphous carbon (a-C) thin films were deposited on quartz substrate at various temperatures with thermal chemical vapor deposition (CVD) technique using methane gas as precursor. The deposited a-C thin films were characterized by Current Voltage (I–V) Measurement and UV-VIS-NIR Spectrophotometer. In this experiment, the pyrolysis process was successful to analyse the electrical and optical properties of a-C thin films deposited by thermal CVD using methane gas. The a-C films properties are found to significantly vary with the deposition temperatures. At higher deposition temperature, the resistivity is lower and thus gives the conductivity of a-C thin films increased due to the relation between the resistivity and conductivity are inversely proportional.

Electrical properties and Raman characterization of a-C thin films deposited by thermal CVD

Amorphous carbon (a-C) thin films deposited with thermal CVD, have been characterized by a standard two-probe method using Advantest R6243 DC Voltage Current Source/Monitor and SemiPro Curve Software and Raman scattering experiment at an excitation wavelength of 514.5 nm provided by HORIBA Jobin Yvon (HR800) Raman. The films were prepared at various deposition temperatures ranging from 650–900°C. The conductivity of a-C thin films increased proportionally with the deposition temperature and the film deposited at 750°C shows large photoconductivity. ID/IG ratio of Raman spectra increased relatively with the deposition temperature as an indication of the disorderliness of a-C thin films. This is supported by the optical properties measurement whereby the optical band gap decreased from 0.65 to ∼0.0eV due to the increase of sp2 bonded carbon configuration.

The Effect of Deposition Temperature to Photoconductivity Properties of Amorphous Carbon Thin Films Deposited By Thermal CVD

Amorphous carbon (a‐C) thin films were deposited by thermal chemical vapor deposition (CVD) using camphor oil on quartz substrates. The photoconductivity and optical properties of the thin films were studied with varying the deposition temperatures ranging from 650 to 900 °C. The film deposited at 750 °C shows large photoconductivity compare to other films. The optical characterization shows that the optical band gap of the thin films decreased from 0.65 to ∼0.0eV with increasing the deposition temperature due to the increase of sp2 bonded carbon configuration. The electrical conductivity of the thin films grown at higher temperature is much higher compared with the thin films deposited at low temperature.

Preparation of pyrolyzed a-C thin films using methane as precursor

Amorphous carbon thin films have been grown on quartz substrates by an economical and simple technique, thermal CVD system with methane as starting material. Since, the decomposition of methane required high thermal energy, thus the deposition temperatures were varied from 700–1000°C. The formation of a-C thin films and its properties were characterized using UV-Vis Spectrophotometer and Advantest R6243 DC Voltage Current Source/Monitor and SemiPro Curve Software.

Properties of Amorphous Carbon Thin Films for Solar Cell Applications

This paper is presented the properties of amorphous carbon (a‐C) thin films for solar cell application. Amorphous carbon thin films have been deposited on silicon substrate by thermal chemical vapor deposition (thermal‐CVD) method at various deposition temperatures. The surface morphology, electrical properties and crystallinity of these films have been studied using Analytical Scanning Electron Microscope (SEM) JEOL JSM‐6360LA, Current Voltage (I‐V) Measurement (Advantest R6243 DC Voltage Current Source/Monitor Software) and the D5000 Siemen Difractrometer (XRD) respectively . It was found that increasing deposition temperature had the most influence on the a‐C thin films properties. In addition the carrier gas flow also showed a secondary impact on the properties of a‐C thin films.

Influence of increasing deposition temperature on opto-electrical properties of amorphous carbon thin film

Amorphous carbon (a-C) thin films were deposited on silicon (Si) substrate by pyrolysing camphor oil at various temperatures with thermal chemical vapor deposition (CVD) technique. The deposited a-C thin films were characterized by Current-Voltage (I-V) Measurement and UV-VIS-NIR Spectrophotometer. The electrical and optical properties of these films have been studied. It was found that increasing deposition temperature had influence on the a-C thin films properties. In addition the carrier gas flow showed a secondary impact on the properties of a-C thin films. The resistivity of a-C thin films decreases when the deposition temperature increases. However, at higher deposition temperature the conductivity increases due to the formation of more disorder sp2 carbon site.

Nitrogenated amorphous carbon film by thermal chemical vapor deposition

The comparison in term of both electrical and structural properties of amorphous carbon (a-C) thin film and nitrogenated amorphous carbon (a-C:N) thin film deposited at 750 °C has been done. The deposition of those films by thermal chemical vapour deposition (TCVD) technique involved argon (Ar) gas, nitrogen gas (N2) and camphor oil as carrier gas, dopant and carbon source respectively. The electrical and structural characterizations were based on Advantest R6243 DC Voltage Current Source/Monitor and SemiPro Curve Software and Scanning Electron Microscopy (SEM). There are significant changes in electrical properties and surface morphology for a-C and a-C:N thin films due to the arrangement of nitrogen atoms.

Modeling and simulation of microscopic defects in CIS-based solar cell thin film using silvaco TCAD

Reactively sputtered copper indium sulfide (CIS) chalcopyrite semiconductor has been actively studied as the potential absorber layer for solar cell thin film application. Using sputtering technique however could result in the formation of several types of defects for example microscopic defects. Microscopic defects are formed within the absorber layer due to the formation of pinholes after surface treatment process. Since the effects of the formation of pinholes in CIS-based thin film solar cell is not well understood yet, a detail study is therefore necessary. In this work, a solar cell model was developed and simulated using Silvaco TCAD tools. Cylindrical pinholes of various diameters and depths were created and analyzed. The simulation results predicted that the number and depth of the pinholes affect the performance of the CIS-based thin film solar cell. The variation of pinhole diameter however did not exhibit any significant effect. It was found that the increases in the number of the pinholes resulted in the increases of solar cell efficiency. The efficiency was predicted to be of around 17.5% when ten pinholes existed within the CIS layer. No significant effect was found as the diameter of the pinhole became wider. Deeper the pinhole depth into the layer however produced the solar cell efficiency of only 1.37%.

Effect of deposition temperature to electrical, structural and optical properties of amorphous carbon thin film prepared by TCVD

Amorphous carbon (a-C) thin films have been prepared by thermal chemical vapor deposition (TCVD) technique at different temperature. The preparation involved argon (Ar), and camphor as carrier gas and carbon source respectively. The effects of deposition temperature in the a-C thin film on electrical, structural and optical properties was characterized by using Advantest R6243 DC Voltage Current Source/Monitor and SemiPro Curve Software, Scanning Electron Microscopy (SEM) and UV-VIS-NIR spectroscopy. The current-voltage (I-V) measurement studies demonstrate that the conductivity increased along the deposition temperature. There are also significant changes in structural and optical band gap as deposition temperature varies.